nfp: add VF and PF representors to flower app

Initialise VF and PF representors in flower app.

Based in part on work by Benjamin LaHaise, Bert van Leeuwen and
Jakub Kicinski.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>